如何知道电子邮件欺骗是否成功？

Just for knowledge purposes, I want to know if it is possible to know if email spoofing has been done successful or not . Suppose if I am sending an email from one's account, What if receiver doesn't exist? Means will i get any error as a spoofer that receiver doesn't exist and you cant send email . ThanksJust for knowledge purposes, I want to know if